Propane/butane dehydrogenation complex with thermal oxidation system

Patent metadata

Field	Value
Publication number	US-12017984-B2
Application number	US-202117362378-A
Country	US
Kind code	B2
Filing date	Jun 29, 2021
Priority date	Aug 4, 2020
Publication date	Jun 25, 2024
Grant date	Jun 25, 2024

Abstract

A process for the treatment of sulfidic spent caustic, conditioned catalyst regeneration vent gas, C4 isomerization off gas, various and hydrocarbon containing liquid and gaseous streams in addition to toxic containing streams like cyanidic off gas and waste water in a propane/butane dehydrogenation complex is described. Various effluent streams are combined in appropriate collection vessels, including an off-gas knockout drum, a hydrocarbon buffer vessel, a spent caustic buffer vessel, an optional a waste water buffer vessel, and a fuel gas knockout drum. Streams from these vessels are sent to a thermal oxidation system.

First claim

What is claimed is:

1. An integrated propane or butane dehydrogenation and thermal oxidation process, the process comprising:
dehydrogenating an alkane feed stream comprising propane, butane, or mixtures thereof in a dehydrogenation reaction zone in the presence of a dehydrogenation catalyst under dehydrogenation conditions to form a dehydrogenated product stream comprising propylene, iso-butylene, or mixtures thereof;
recovering the dehydrogenated product stream and thereby producing a sulfidic spent caustic stream and a spent solvent stream;
at least one of:
introducing the sulfidic spent caustic stream from a regenerant gas scrubbing zone into a spent caustic buffer vessel;
introducing at least one of the spent solvent stream from a solvent recovery section, and a purge stream into a hydrocarbon buffer vessel; and

thermally oxidizing at least one of the sulfidic spent caustic stream from the spent caustic buffer vessel, a liquid hydrocarbon stream from the hydrocarbon buffer vessel,

an off-gas stream from an off-gas knockout drum, and a fuel gas stream from a fuel gas knockout drum in a thermal oxidation system.

2. The process of claim 1 wherein thermally oxidizing the at least one of the sulfidic spent caustic stream, the liquid hydrocarbon stream, the off-gas stream, and the fuel gas stream comprises:
thermally oxidizing the at least one of the sulfidic spent caustic stream, the liquid hydrocarbon stream, the off-gas stream, and the fuel gas stream in a thermal oxidizing section to form a flue gas consisting essentially of at least one of H 2 O, Na 2 CO 3 , Na 2 SO 3 , Na 2 SO 4 , CO 2 , N 2 , O 2 , SOx, NOx, NaCl, HCl, Cl 2 , dioxins, and furans;
optionally recovering waste heat from the flue gas in a waste heat recovery section;
removing at least one of SOx, HCl, and Cl 2 from the flue gas in a SOx removal section to form a de-SOx outlet flue gas consisting essentially of at least one of H 2 O, CO 2 , N 2 , O 2 , NOx, dioxins, and furans, wherein removing the at least one of SOx, HCl, and Cl 2 from the flue gas comprises:
quenching the flue gas in a quench section to form quenched flue gas after recovering the waste heat; and
contacting a caustic solution or an NH 3 based solution with the quenched flue gas in a SOx scrubbing section to form the de-SOx outlet flue gas and a liquid stream comprising at least one of H 2 O, Na 2 SO 3 , Na 2 SO 4 , NaHSO3, Na 2 CO 3 , NaCl, (NH 4 )SO 4 , and NH 4 Cl;
or
reacting the flue gas with a reactant in an SOx reaction section to form a reaction section flue gas consisting essentially of at least one of H 2 O, CO 2 , N 2 , O 2 , NaCl, Na 2 CO 3 , Na 2 SO 4 , NaNO 3 , CaCl 2 , CaSO 4 , Ca(NO 3 ) 2 , MgCl 2 , MgCO 3 , MgSO 4 , Mg(NO 3 ) 2 , NOx, Cl 2 , dioxins, and furans, wherein the reactant comprises at least one of NaHCO 3 , NaHCO 3 ·Na 2 CO 3 ·2(H 2 O), CaCO 3 , Ca(OH) 2 , and Mg(OH) 2 ; and
optionally filtering the reaction section flue gas in a filter section to remove at least one of NaCl, Na 2 CO 3 , Na 2 SO 4 , NaNO 3 , CaCl 2 , CaCO 3 , CaSO 4 , Ca(NO 3 ) 2 , MgCl 2 , MgCO 3 , MgSO 4 , and Mg(NO3)2 to form the de-SOx outlet flue gas;

optionally removing NOx from the de-SOx outlet flue gas in a NOx removal section to form a de-NOx outlet flue gas consisting essentially of at least one of H 2 O, CO 2 , N 2 , O 2 , dioxins, and furans; and
optionally removing dioxin, furan, or both in a dioxin-furan removal section from the de-SOx outlet flue gas or the de-NOx outlet flue gas to form a treated outlet flue gas consisting essentially of at least one of H 2 O, CO 2 , N 2 , and O 2 .

3. The process of claim 1 wherein recovering the dehydrogenated product stream comprises:
cooling the dehydrogenated product stream;
passing the cooled dehydrogenated product stream to an adsorbent bed to produce a purified dehydrogenated product stream;
separating the purified dehydrogenated product stream into a recycle feed stream comprising unreacted propane, butane, or mixtures thereof, a recovered dehydrogenated product stream comprising the propylene, iso-butylene, or mixtures thereof, and a net gas stream comprising hydrogen in a cryogenic separation zone:
regenerating the adsorbent bed by passing at least a portion of the net gas stream from the cryogenic separation zone to the adsorbent bed and forming a regenerant gas stream;
introducing a NaOH stream and the regenerant gas stream into a regenerant gas scrubbing zone to remove sulfur from the regenerant gas stream, thus forming the sulfidic spent caustic stream and a scrubbed regenerant gas stream;
introducing the sulfidic spent caustic stream to the spent caustic buffer vessel; and
at least one of:
passing at least a portion of the net gas stream from the cryogenic separation zone to a hydrogen purification zone forming a purified hydrogen stream and a tail gas stream;
passing at least a portion of the tail gas stream to at least one of a fired heater as fuel and the fuel gas knockout drum;
passing the scrubbed regenerant gas stream to at least one of the dehydrogenation reaction zone, the hydrogen purification zone, and the fuel gas knockout drum; and
passing at least a portion of the net gas stream from the cryogenic separation zone to the fuel gas knockout drum.

4. The process of claim 1 further comprising:
controlling a pressure in at least one of the spent caustic buffer vessel and the hydrocarbon buffer vessel in a push-pull system by introducing a gas stream comprising at least one of fuel gas, off-gas, or waste gas into at least one of the spent caustic buffer vessel and the hydrocarbon buffer vessel;
sending an excess gas stream from the spent caustic buffer vessel or the hydrocarbon buffer vessel to the off-gas knockout drum;
separating a liquid stream from the excess gas stream in the off-gas knockout drum; and
passing the liquid stream to the hydrocarbon buffer vessel.

5. The process of claim 1 , further comprising
passing the dehydrogenated product stream to a propylene-iso-butylene derivative process unit to form a propylene-iso-butylene derivative product comprising a propylene derivative product, an iso-butylene derivative product, or mixtures thereof, and at least one of a gaseous effluent, a hydrocarbon liquid effluent, and an aqueous effluent;
recovering the propylene-iso-butylene derivative product;
passing at least one of: the gaseous effluent to the off-gas knockout drum, and the hydrocarbon liquid effluent to the hydrocarbon buffer vessel; and
optionally passing the aqueous effluent to an aqueous effluent treatment plant.

6. The process of claim 5 wherein the propylene-iso-butylene derivative process unit comprises a propylene derivative process unit comprising a polymerization unit, further comprising:
polymerizing the propylene in a polymerization section to form the propylene derivative product comprising polypropylene;
separating the polypropylene from the propylene in a monomer recovery section using steam, thus forming a polypropylene stream and a steamer off-gas stream;
optionally extruding the polypropylene stream in an extruder section to form a polypropylene product and a tempered water bleed stream;
passing at least one of the steamer off-gas stream from the monomer recovery unit to the fuel gas knockout drum, and the tempered water bleed stream from the extruder section to a waste water buffer vessel; and
thermally oxidizing a waste water stream from the waste water buffer vessel.

7. The process of claim 5 wherein the propylene-iso-butylene derivative process unit comprises a propylene derivative process unit comprising an acrylonitrile unit, further comprising:
reacting the propylene with ammonia and air in an ammoxidation reaction section to form an acrylonitrile reaction mixture;
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Assignees

• Honeywell Int Inc

Inventors

• De Menezes Rui
• De Ren Jan
• Jackson Tom
• Desai Madan K M
• Kanyuh Adam J

Classifications

• B01D2257/2025

  Chlorine · CPC title

• B01D2257/2045

  Hydrochloric acid · CPC title

• B01D2257/302

  Sulfur oxides · CPC title

• B01D2258/0283

  Flue gases · CPC title

• B01D2259/416

  involving cryogenic temperature treatment · CPC title